101
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Xing Z, Zeng M, Hu H, Zhang H, Hao Z, Long Y, Chen S, Su H, Yuan Z, Xu M, Chen J. Fragile X mental retardation protein promotes astrocytoma proliferation via the MEK/ERK signaling pathway. Oncotarget 2018; 7:75394-75406. [PMID: 27683117 PMCID: PMC5342749 DOI: 10.18632/oncotarget.12215] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 09/12/2016] [Indexed: 12/16/2022] Open
Abstract
Objective To examine the association between fragile X mental retardation protein (FMRP) expression and astrocytoma characteristics. Methods Pathologic grade and expressions of glial fibrillary acidic protein (GFAP), Ki67 (proliferation marker), and FMRP were determined in astrocytoma specimens from 74 patients. Kaplan-Meier survival analysis was undertaken. Pathologic grade and protein levels of FMRP were determined in 24 additional patients with astrocytoma and 6 controls (cerebral trauma). In cultured U251 and U87 cell lines, the effects of FMRP knock-down on cell proliferation, AKT/mTOR/GSK-3β and MEK/ERK signaling were studied. The effects of FMRP knock-down on the volumes and weights of U251 cell-derived orthotopic tumors in mice were investigated. Results In patients, FMRP expression was increased in grade IV (5.1-fold, P<0.01) and grade III (3.2-fold, P<0.05) astrocytoma, compared with controls. FMRP and Ki67 expressions were positively correlated (R2=0.877, P<0.001). Up-regulation of FMRP was associated with poorer survival among patients with FMRP integrated optical density >30 (P<0.01). In astrocytoma cell lines, FMRP knock-down slowed proliferation (P<0.05), inhibited total MEK levels P<0.05, and reduced phosphorylation of MEK (Ser217/221) and ERK (Thr202/Tyr204) (P<0.05). In mice with orthotopic tumors, FMRP knock-down decreased FMRP and Ki67 expressions, and reduced tumor volume and weight (36.3% or 61.5% on day 15, both P<0.01). Also, phosphorylation of MEK (Ser217/221) and ERK (Thr202/Tyr204), and total MEK in xenografts were decreased in sh-FMRP xenografts compared with non-transfected ones (all P<0.05). Conclusion Enhanced FMRP expression in astrocytoma may promote proliferation through activation of MEK/ERK signaling.
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Affiliation(s)
- Zhou Xing
- Department of Oncology, The First Affiliated Hospital, Jinan University, Guangzhou 510632, People's Republic of China.,Department of Neurosurgery, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, People's Republic of China
| | - Minling Zeng
- Department of Neurosurgery, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, People's Republic of China
| | - Huixian Hu
- Translational Medicine Center, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, People's Republic of China
| | - Hui Zhang
- Translational Medicine Center, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, People's Republic of China
| | - Zhuofang Hao
- Department of Pathology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, People's Republic of China
| | - Yuesheng Long
- Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and Ministry of Education of China, Guangzhou Medical University, Guangzhou 510260, People's Republic of China
| | - Shengqiang Chen
- Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and Ministry of Education of China, Guangzhou Medical University, Guangzhou 510260, People's Republic of China
| | - Hang Su
- Translational Medicine Center, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, People's Republic of China
| | - Zhongmin Yuan
- Department of Neurosurgery, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, People's Republic of China.,Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and Ministry of Education of China, Guangzhou Medical University, Guangzhou 510260, People's Republic of China
| | - Meng Xu
- Department of Oncology, The First Affiliated Hospital, Jinan University, Guangzhou 510632, People's Republic of China
| | - Jingqi Chen
- Translational Medicine Center, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, People's Republic of China.,Department of Medical Oncology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, People's Republic of China
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102
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Gurney ME, Cogram P, Deacon RM, Rex C, Tranfaglia M. Multiple Behavior Phenotypes of the Fragile-X Syndrome Mouse Model Respond to Chronic Inhibition of Phosphodiesterase-4D (PDE4D). Sci Rep 2017; 7:14653. [PMID: 29116166 PMCID: PMC5677090 DOI: 10.1038/s41598-017-15028-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 10/18/2017] [Indexed: 01/14/2023] Open
Abstract
Fragile-X syndrome (FXS) patients display intellectual disability and autism spectrum disorder due to silencing of the X-linked, fragile-X mental retardation-1 (FMR1) gene. Dysregulation of cAMP metabolism is a consistent finding in patients and in the mouse and fly FXS models. We therefore explored if BPN14770, a prototypic phosphodiesterase-4D negative allosteric modulator (PDE4D-NAM) in early human clinical trials, might provide therapeutic benefit in the mouse FXS model. Daily treatment of adult male fmr1 C57Bl6 knock-out mice with BPN14770 for 14 days reduced hyperarousal, improved social interaction, and improved natural behaviors such as nesting and marble burying as well as dendritic spine morphology. There was no decrement in behavioral scores in control C57Bl6 treated with BPN14770. The behavioral benefit of BPN14770 persisted two weeks after washout of the drug. Thus, BPN14770 may be useful for the treatment of fragile-X syndrome and other disorders with decreased cAMP signaling.
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Affiliation(s)
- Mark E Gurney
- Tetra Discovery Partners, Inc, Grand Rapids, MI, USA.
| | - Patricia Cogram
- FRAXA-DVI, FRAXA, Santiago, Chile.,Laboratory of Molecular Neuropsychiatry, Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro University, National Scientific and Technical Research Council, Buenos Aires, Argentina.,IEB, Faculty of Science, University of Chile, Santiago, Chile
| | - Robert M Deacon
- FRAXA-DVI, FRAXA, Santiago, Chile.,Laboratory of Molecular Neuropsychiatry, Institute of Cognitive and Translational Neuroscience (INCyT), INECO Foundation, Favaloro University, National Scientific and Technical Research Council, Buenos Aires, Argentina.,IEB, Faculty of Science, University of Chile, Santiago, Chile
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103
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Pyronneau A, He Q, Hwang JY, Porch M, Contractor A, Zukin RS. Aberrant Rac1-cofilin signaling mediates defects in dendritic spines, synaptic function, and sensory perception in fragile X syndrome. Sci Signal 2017; 10:10/504/eaan0852. [PMID: 29114038 DOI: 10.1126/scisignal.aan0852] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Fragile X syndrome (FXS) is the most common inherited cause of intellectual disabilities and a leading cause of autism. FXS is caused by a trinucleotide expansion in the gene FMR1 on the X chromosome. The neuroanatomical hallmark of FXS is an overabundance of immature dendritic spines, a factor thought to underlie synaptic dysfunction and impaired cognition. We showed that aberrantly increased activity of the Rho GTPase Rac1 inhibited the actin-depolymerizing factor cofilin, a major determinant of dendritic spine structure, and caused disease-associated spine abnormalities in the somatosensory cortex of FXS model mice. Increased cofilin phosphorylation and actin polymerization coincided with abnormal dendritic spines and impaired synaptic maturation. Viral delivery of a constitutively active cofilin mutant (cofilinS3A) into the somatosensory cortex of Fmr1-deficient mice rescued the immature dendritic spine phenotype and increased spine density. Inhibition of the Rac1 effector PAK1 with a small-molecule inhibitor rescued cofilin signaling in FXS mice, indicating a causal relationship between PAK1 and cofilin signaling. PAK1 inhibition rescued synaptic signaling (specifically the synaptic ratio of NMDA/AMPA in layer V pyramidal neurons) and improved sensory processing in FXS mice. These findings suggest a causal relationship between increased Rac1-cofilin signaling, synaptic defects, and impaired sensory processing in FXS and uncover a previously unappreciated role for impaired Rac1-cofilin signaling in the aberrant spine morphology and spine density associated with FXS.
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Affiliation(s)
- Alexander Pyronneau
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Qionger He
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Jee-Yeon Hwang
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Morgan Porch
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Anis Contractor
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.,Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208, USA
| | - R Suzanne Zukin
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA.
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104
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Zhang K, Li YJ, Guo Y, Zheng KY, Yang Q, Yang L, Wang XS, Song Q, Chen T, Zhuo M, Zhao MG. Elevated progranulin contributes to synaptic and learning deficit due to loss of fragile X mental retardation protein. Brain 2017; 140:3215-3232. [DOI: 10.1093/brain/awx265] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 08/20/2017] [Indexed: 01/09/2023] Open
Affiliation(s)
- Kun Zhang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, 710032l, China
| | - Yu-jiao Li
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, 710032l, China
| | - Yanyan Guo
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, 710032l, China
| | - Kai-yin Zheng
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, 710032l, China
| | - Qi Yang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, 710032l, China
| | - Le Yang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, 710032l, China
| | - Xin-shang Wang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, 710032l, China
| | - Qian Song
- Center for Neuron and Disease, Frontier Institutes of Life Science and of Science and Technology, Xi’an Jiaotong University, Xi’an, 710032, China
| | - Tao Chen
- Center for Neuron and Disease, Frontier Institutes of Life Science and of Science and Technology, Xi’an Jiaotong University, Xi’an, 710032, China
- Department of Anatomy, Histology and Embryology and K.K. Leung Brain Research Center, Fourth Military Medical University, Xi’an, 710032, China
| | - Min Zhuo
- Center for Neuron and Disease, Frontier Institutes of Life Science and of Science and Technology, Xi’an Jiaotong University, Xi’an, 710032, China
| | - Ming-gao Zhao
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, 710032l, China
- Center for Neuron and Disease, Frontier Institutes of Life Science and of Science and Technology, Xi’an Jiaotong University, Xi’an, 710032, China
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105
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Ceolin L, Bouquier N, Vitre-Boubaker J, Rialle S, Severac D, Valjent E, Perroy J, Puighermanal E. Cell Type-Specific mRNA Dysregulation in Hippocampal CA1 Pyramidal Neurons of the Fragile X Syndrome Mouse Model. Front Mol Neurosci 2017; 10:340. [PMID: 29104533 PMCID: PMC5655025 DOI: 10.3389/fnmol.2017.00340] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 10/06/2017] [Indexed: 12/19/2022] Open
Abstract
Fragile X syndrome (FXS) is a genetic disorder due to the silencing of the Fmr1 gene, causing intellectual disability, seizures, hyperactivity, and social anxiety. All these symptoms result from the loss of expression of the RNA binding protein fragile X mental retardation protein (FMRP), which alters the neurodevelopmental program to abnormal wiring of specific circuits. Aberrant mRNAs translation associated with the loss of Fmr1 product is widely suspected to be in part the cause of FXS. However, precise gene expression changes involved in this disorder have yet to be defined. The objective of this study was to identify the set of mistranslated mRNAs that could contribute to neurological deficits in FXS. We used the RiboTag approach and RNA sequencing to provide an exhaustive listing of genes whose mRNAs are differentially translated in hippocampal CA1 pyramidal neurons as the integrative result of FMRP loss and subsequent neurodevelopmental adaptations. Among genes differentially regulated between adult WT and Fmr1-/y mice, we found enrichment in FMRP-binders but also a majority of non-FMRP-binders. Interestingly, both up- and down-regulation of specific gene expression is relevant to fully understand the molecular deficiencies triggering FXS. More importantly, functional genomic analysis highlighted the importance of genes involved in neuronal connectivity. Among them, we show that Klk8 altered expression participates in the abnormal hippocampal dendritic spine maturation observed in a mouse model of FXS.
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Affiliation(s)
- Laura Ceolin
- IGF, CNRS, INSERM, Univ. Montpellier, Montpellier, France
| | | | | | | | - Dany Severac
- Montpellier GenomiX c/o IGF, Montpellier, France
| | | | - Julie Perroy
- IGF, CNRS, INSERM, Univ. Montpellier, Montpellier, France
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106
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Mila M, Alvarez-Mora M, Madrigal I, Rodriguez-Revenga L. Fragile X syndrome: An overview and update of the FMR1
gene. Clin Genet 2017; 93:197-205. [DOI: 10.1111/cge.13075] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 06/09/2017] [Accepted: 06/10/2017] [Indexed: 01/31/2023]
Affiliation(s)
- M. Mila
- Biochemistry and Molecular Genetics Department, Hospital Clinic; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Barcelona Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER); Instituto de Salud Carlos III; Madrid Spain
| | - M.I. Alvarez-Mora
- Biochemistry and Molecular Genetics Department, Hospital Clinic; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Barcelona Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER); Instituto de Salud Carlos III; Madrid Spain
| | - I. Madrigal
- Biochemistry and Molecular Genetics Department, Hospital Clinic; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Barcelona Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER); Instituto de Salud Carlos III; Madrid Spain
| | - L. Rodriguez-Revenga
- Biochemistry and Molecular Genetics Department, Hospital Clinic; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS); Barcelona Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER); Instituto de Salud Carlos III; Madrid Spain
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107
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Mahmood U, Ahn S, Yang EJ, Choi M, Kim H, Regan P, Cho K, Kim HS. Dendritic spine anomalies and PTEN alterations in a mouse model of VPA-induced autism spectrum disorder. Pharmacol Res 2017; 128:110-121. [PMID: 28823725 DOI: 10.1016/j.phrs.2017.08.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 08/08/2017] [Accepted: 08/12/2017] [Indexed: 11/18/2022]
Abstract
Mounting evidence suggests that the etiology of autism spectrum disorders (ASDs) is profoundly influenced by exposure to environmental factors, although the precise molecular and cellular links remain ill-defined. In this study, we examined how exposure to valproic acid (VPA) during pregnancy is associated with an increased incidence of ASD. A mouse model was established by injecting VPA at embryonic day 13, and its behavioral phenotypes including impaired social interaction, increased repetitive behaviors and decreased nociception were observed at postnatal days 21-42. VPA-treated mice showed dysregulation of synaptic structure in cortical neurons, including a reduced proportion of filopodium-type and stubby spines and increased proportions of thin and mushroom-type spines, along with a decreased spine head size. We also found that VPA-treatment led to decreased expression of phosphate and tensin homolog (PTEN) and increased levels of p-AKT protein in the hippocampus and cortex. Our data suggest that there is a correlation between VPA exposure and dysregulation of PTEN with ASD-like behavioral and neuroanatomical changes, and this may be a potential mechanism of VPA-induced ASD.
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Affiliation(s)
- Usman Mahmood
- Interdisciplinary Program in Brain Sciences, Seoul National University College of Natural Sciences, Seoul, 08826, Republic of Korea
| | - Sangzin Ahn
- Department of Pharmacology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea; Present address: Department of Pharmacology, Inje University College of Medicine, Busan, 47392, Republic of Korea
| | - Eun-Jeong Yang
- Department of Pharmacology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Moonseok Choi
- Department of Pharmacology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Hyunju Kim
- Department of Pharmacology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Philip Regan
- School of Clinical Sciences, Faculty of Health Sciences, University of Bristol, Whitson Street, Bristol BS1 3NY, United Kingdom
| | - Kwangwook Cho
- School of Clinical Sciences, Faculty of Health Sciences, University of Bristol, Whitson Street, Bristol BS1 3NY, United Kingdom
| | - Hye-Sun Kim
- Interdisciplinary Program in Brain Sciences, Seoul National University College of Natural Sciences, Seoul, 08826, Republic of Korea; Department of Pharmacology and Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea; Seoul National University Bundang Hospital, Seoul National University College of Medicine, Sungnam, 13620, Republic of Korea.
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108
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Korb E, Herre M, Zucker-Scharff I, Gresack J, Allis CD, Darnell RB. Excess Translation of Epigenetic Regulators Contributes to Fragile X Syndrome and Is Alleviated by Brd4 Inhibition. Cell 2017; 170:1209-1223.e20. [PMID: 28823556 DOI: 10.1016/j.cell.2017.07.033] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 05/17/2017] [Accepted: 07/21/2017] [Indexed: 11/28/2022]
Abstract
Fragile X syndrome (FXS) is a leading genetic cause of intellectual disability and autism. FXS results from the loss of function of fragile X mental retardation protein (FMRP), which represses translation of target transcripts. Most of the well-characterized target transcripts of FMRP are synaptic proteins, yet targeting these proteins has not provided effective treatments. We examined a group of FMRP targets that encode transcriptional regulators, particularly chromatin-associated proteins. Loss of FMRP in mice results in widespread changes in chromatin regulation and aberrant gene expression. To determine if targeting epigenetic factors could reverse phenotypes associated with the disorder, we focused on Brd4, a BET protein and chromatin reader targeted by FMRP. Inhibition of Brd4 function alleviated many of the phenotypes associated with FXS. We conclude that loss of FMRP results in significant epigenetic misregulation and that targeting transcription via epigenetic regulators like Brd4 may provide new treatments for FXS.
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Affiliation(s)
- Erica Korb
- Laboratory of Chromatin Biology and Epigenetics, The Rockefeller University, New York, NY 10065, USA
| | - Margaret Herre
- Laboratory of Molecular Neuro-oncology and Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
| | - Ilana Zucker-Scharff
- Laboratory of Molecular Neuro-oncology and Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA
| | - Jodi Gresack
- Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, NY 10065, USA
| | - C David Allis
- Laboratory of Chromatin Biology and Epigenetics, The Rockefeller University, New York, NY 10065, USA.
| | - Robert B Darnell
- Laboratory of Molecular Neuro-oncology and Howard Hughes Medical Institute, The Rockefeller University, New York, NY 10065, USA.
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109
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Zhang K, Li YJ, Feng D, Zhang P, Wang YT, Li X, Liu SB, Wu YM, Zhao MG. Imbalance between TNFα and progranulin contributes to memory impairment and anxiety in sleep-deprived mice. Sci Rep 2017; 7:43594. [PMID: 28300056 PMCID: PMC5353617 DOI: 10.1038/srep43594] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 01/25/2017] [Indexed: 12/21/2022] Open
Abstract
Sleep disorder is becoming a widespread problem in current society, and is associated with impaired cognition and emotional disorders. Progranulin (PGRN), also known as granulin epithelin precursor, promotes neurite outgrowth and cell survival, and is encoded by the GRN gene. It is a tumor necrosis factor α receptor (TNFR) ligand which is implicated in many central nervous system diseases. However, the role PGRN in sleep disorder remains unclear. In the present study, we found that sleep deprivation (S-DEP) impaired the memory and produced thigmotaxis/anxiety-like behaviors in mice. S-DEP increased the levels of TNFα but decreased PGRN levels in the hippocampus. The intracerebroventricular (ICV) injection of PGRN or intraperitoneal injection of TNFα synthesis blocker thalidomide (25 mg/kg), prevented the memory impairment and anxiety behaviors induced by S-DEP. PGRN treatment also restored dendritic spine density in the hippocampus CA1 region and neurogenesis in hippocampus dentate gyrus (DG). These results indicate that an imbalance between TNFα and PGRN contributes to memory impairment and thigmotaxis/anxiety caused by sleep deprivation.
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Affiliation(s)
- Kun Zhang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, China.,Precision Pharmacy &Drug Development Center, Tangdu Hospital, Fourth Military Medical University, Xi'an, 710038, China
| | - Yu-Jiao Li
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, China
| | - Dan Feng
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, China.,Department of Radiology, Tangdu Hospital, Fourth Military Medical University, Xi'an, 710038, China
| | - Peng Zhang
- Department of Neurobiology, Capital Medical University, Beijing, 100069, China
| | - Ya-Tao Wang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, China
| | - Xiang Li
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, China
| | - Shui-Bing Liu
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, China
| | - Yu-Mei Wu
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, China
| | - Ming-Gao Zhao
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, China.,Precision Pharmacy &Drug Development Center, Tangdu Hospital, Fourth Military Medical University, Xi'an, 710038, China
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110
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Scharkowski F, Frotscher M, Lutz D, Korte M, Michaelsen-Preusse K. Altered Connectivity and Synapse Maturation of the Hippocampal Mossy Fiber Pathway in a Mouse Model of the Fragile X Syndrome. Cereb Cortex 2017; 28:852-867. [DOI: 10.1093/cercor/bhw408] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 12/22/2016] [Indexed: 12/12/2022] Open
Affiliation(s)
- F Scharkowski
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, 38106 Braunschweig, Germany
| | - Michael Frotscher
- ZMNH, Institute for Structural Neurobiology, D-20251 Hamburg, Germany
| | - David Lutz
- ZMNH, Institute for Structural Neurobiology, D-20251 Hamburg, Germany
| | - Martin Korte
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, 38106 Braunschweig, Germany
- Helmholtz Centre for Infection Research, AG NIND, 38124 Braunschweig, Germany
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111
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Kondratiuk I, Łęski S, Urbańska M, Biecek P, Devijver H, Lechat B, Van Leuven F, Kaczmarek L, Jaworski T. GSK-3β and MMP-9 Cooperate in the Control of Dendritic Spine Morphology. Mol Neurobiol 2017; 54:200-211. [PMID: 26738851 PMCID: PMC5219889 DOI: 10.1007/s12035-015-9625-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 12/08/2015] [Indexed: 11/02/2022]
Abstract
Changes in the morphology of dendritic spines are prominent during learning and in different neurological and neuropsychiatric diseases, including those in which glycogen synthase kinase-3β (GSK-3β) has been implicated. Despite much evidence of the involvement of GSK-3β in functional synaptic plasticity, it is unclear how GSK-3β controls structural synaptic plasticity (i.e., the number and shape of dendritic spines). In the present study, we used two mouse models overexpressing and lacking GSK-3β in neurons to investigate how GSK-3β affects the structural plasticity of dendritic spines. Following visualization of dendritic spines with DiI dye, we found that increasing GSK-3β activity increased the number of thin spines, whereas lacking GSK-3β increased the number of stubby spines in the dentate gyrus. Under conditions of neuronal excitation, increasing GSK-3β activity caused higher activity of extracellularly acting matrix metalloproteinase-9 (MMP-9), and MMP inhibition normalized thin spines in GSK-3β overexpressing mice. Administration of the nonspecific GSK-3β inhibitor lithium in animals with active MMP-9 and animals lacking MMP-9 revealed that GSK-3β and MMP-9 act in concert to control dendritic spine morphology. Altogether, our data demonstrate that the dysregulation of GSK-3β activity has dramatic consequences on dendritic spine morphology, implicating MMP-9 as a mediator of GSK-3β-induced synaptic alterations.
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Affiliation(s)
- Ilona Kondratiuk
- Laboratory of Neurobiology, The Nencki Institute of Experimental Biology, 3 Pasteur, 02-093, Warsaw, Poland
| | - Szymon Łęski
- Laboratory of Neuroinformatics, The Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Małgorzata Urbańska
- Laboratory of Molecular and Cellular Neurobiology, The International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Przemysław Biecek
- Faculty of Mathematics, Informatics, and Mechanics, University of Warsaw, Warsaw, Poland
| | - Herman Devijver
- Department of Human Genetics, Experimental Genetics Group - LEGTEGG, KULeuven, Leuven, Belgium
| | - Benoit Lechat
- Department of Human Genetics, Experimental Genetics Group - LEGTEGG, KULeuven, Leuven, Belgium
| | - Fred Van Leuven
- Department of Human Genetics, Experimental Genetics Group - LEGTEGG, KULeuven, Leuven, Belgium
| | - Leszek Kaczmarek
- Laboratory of Neurobiology, The Nencki Institute of Experimental Biology, 3 Pasteur, 02-093, Warsaw, Poland.
| | - Tomasz Jaworski
- Laboratory of Neurobiology, The Nencki Institute of Experimental Biology, 3 Pasteur, 02-093, Warsaw, Poland.
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Ismail FY, Fatemi A, Johnston MV. Cerebral plasticity: Windows of opportunity in the developing brain. Eur J Paediatr Neurol 2017; 21:23-48. [PMID: 27567276 DOI: 10.1016/j.ejpn.2016.07.007] [Citation(s) in RCA: 317] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 07/06/2016] [Indexed: 12/31/2022]
Abstract
BACKGROUND Neuroplasticity refers to the inherently dynamic biological capacity of the central nervous system (CNS) to undergo maturation, change structurally and functionally in response to experience and to adapt following injury. This malleability is achieved by modulating subsets of genetic, molecular and cellular mechanisms that influence the dynamics of synaptic connections and neural circuitry formation culminating in gain or loss of behavior or function. Neuroplasticity in the healthy developing brain exhibits a heterochronus cortex-specific developmental profile and is heightened during "critical and sensitive periods" of pre and postnatal brain development that enable the construction and consolidation of experience-dependent structural and functional brain connections. PURPOSE In this review, our primary goal is to highlight the essential role of neuroplasticity in brain development, and to draw attention to the complex relationship between different levels of the developing nervous system that are subjected to plasticity in health and disease. Another goal of this review is to explore the relationship between plasticity responses of the developing brain and how they are influenced by critical and sensitive periods of brain development. Finally, we aim to motivate researchers in the pediatric neuromodulation field to build on the current knowledge of normal and abnormal neuroplasticity, especially synaptic plasticity, and their dependence on "critical or sensitive periods" of neural development to inform the design, timing and sequencing of neuromodulatory interventions in order to enhance and optimize their translational applications in childhood disorders of the brain. METHODS literature review. RESULTS We discuss in details five patterns of neuroplasticity expressed by the developing brain: 1) developmental plasticity which is further classified into normal and impaired developmental plasticity as seen in syndromic autism spectrum disorders, 2) adaptive (experience-dependent) plasticity following intense motor skill training, 3) reactive plasticity to pre and post natal CNS injury or sensory deprivation, 4) excessive plasticity (loss of homeostatic regulation) as seen in dystonia and refractory epilepsy, 6) and finally, plasticity as the brain's "Achilles tendon" which induces brain vulnerability under certain conditions such as hypoxic ischemic encephalopathy and epileptic encephalopathy syndromes. We then explore the unique feature of "time-sensitive heightened plasticity responses" in the developing brain in the in the context of neuromodulation. CONCLUSION The different patterns of neuroplasticity and the unique feature of heightened plasticity during critical and sensitive periods are important concepts for researchers and clinicians in the field of pediatric neurology and neurodevelopmental disabilities. These concepts need to be examined systematically in the context of pediatric neuromodulation. We propose that critical and sensitive periods of brain development in health and disease can create "windows of opportunity" for neuromodulatory interventions that are not commonly seen in adult brain and probably augment plasticity responses and improve clinical outcomes.
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Affiliation(s)
- Fatima Yousif Ismail
- Department of neurology and developmental medicine, The Kennedy Krieger Institute, Johns Hopkins Medical Institutions, MD, USA; Department of pediatrics, College of Medicine and Health Sciences, United Arab Emirates University, Al- Ain, UAE.
| | - Ali Fatemi
- Departments of Neurology and Pediatrics, The Kennedy Krieger Institute, and Johns Hopkins University School of Medicine, MD, USA
| | - Michael V Johnston
- Departments of Neurology and Pediatrics, The Kennedy Krieger Institute, and Johns Hopkins University School of Medicine, MD, USA
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Berry-Kravis E, Des Portes V, Hagerman R, Jacquemont S, Charles P, Visootsak J, Brinkman M, Rerat K, Koumaras B, Zhu L, Barth GM, Jaecklin T, Apostol G, von Raison F. Mavoglurant in fragile X syndrome: Results of two randomized, double-blind, placebo-controlled trials. Sci Transl Med 2016; 8:321ra5. [PMID: 26764156 DOI: 10.1126/scitranslmed.aab4109] [Citation(s) in RCA: 179] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Fragile X syndrome (FXS), the most common cause of inherited intellectual disability and autistic spectrum disorder, is typically caused by transcriptional silencing of the X-linked FMR1 gene. Work in animal models has described altered synaptic plasticity, a result of the up-regulation of metabotropic glutamate receptor 5 (mGluR5)-mediated signaling, as a putative downstream effect. Post hoc analysis of a randomized, placebo-controlled, crossover phase 2 trial suggested that the selective mGluR5 antagonist mavoglurant improved behavioral symptoms in FXS patients with completely methylated FMR1 genes. We present the results of two phase 2b, multicenter, randomized, double-blind, placebo-controlled, parallel-group studies of mavoglurant in FXS, designed to confirm this result in adults (n = 175, aged 18 to 45 years) and adolescents (n = 139, aged 12 to 17 years). In both trials, participants were stratified by methylation status and randomized to receive mavoglurant (25, 50, or 100 mg twice daily) or placebo over 12 weeks. Neither of the studies achieved the primary efficacy end point of improvement on behavioral symptoms measured by the Aberrant Behavior Checklist-Community Edition using the FXS-specific algorithm (ABC-C(FX)) after 12 weeks of treatment with mavoglurant. The safety and tolerability profile of mavoglurant was as previously described, with few adverse events. Therefore, under the conditions of our study, we could not confirm the mGluR theory of FXS nor the ability of the methylation state of the FMR1 promoter to predict mavoglurant efficacy. Preclinical results suggest that future clinical trials might profitably explore initiating treatment in a younger population with longer treatment duration and longer placebo run-ins and identifying new markers to better assess behavioral and cognitive benefits.
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Affiliation(s)
- Elizabeth Berry-Kravis
- Departments of Pediatrics, Neurological Sciences, and Biochemistry, Rush University Medical Center, Chicago, IL 60612, USA
| | - Vincent Des Portes
- National Reference Center for Fragile X and Other X-Linked Intellectual Disabilities, CIC 1407 INSERM, Hospices Civils de Lyon, Université de Lyon, 69002 Lyon, France. CNRS UMR 5304 (Laboratoire sur le Langage, le Cerveau et la Cognition), 69500 Bron, France
| | - Randi Hagerman
- Medical Investigation of Neurodevelopmental Disorders Institute and Department of Pediatrics, UC Davis Medical Center, Sacramento, CA 95817, USA
| | - Sébastien Jacquemont
- Centre Hospitalier Universitaire Vaudois, CH-1011 Lausanne, Switzerland. CHU Sainte-Justine Research Centre, Montreal, Quebec H3T 1C5, Canada
| | - Perrine Charles
- Département de Génétique et Cytogénétique, Unité Fonctionnelle de Génétique Médicale, Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, 75013 Paris, France
| | - Jeannie Visootsak
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | - Karin Rerat
- Novartis Pharmaceuticals SAS, 92500 Rueil-Malmaison, France
| | - Barbara Koumaras
- Neurodegeneration Global Development, Novartis Pharmaceuticals Corporation, East Hanover, NJ 07936-1080, USA
| | - Liansheng Zhu
- Integrated Quantitative Science, Global Development, Novartis Pharmaceuticals Corporation, East Hanover, NJ 07936-1080, USA
| | - Gottfried Maria Barth
- Department of Child and Adolescent Psychiatry, University Hospital of Tübingen, 72076 Tübingen, Baden-Württemberg, Germany
| | - Thomas Jaecklin
- Neuroscience Development, Novartis Pharma AG, CH-4056 Basel, Switzerland
| | - George Apostol
- Neuroscience Development, Novartis Pharma AG, CH-4056 Basel, Switzerland
| | - Florian von Raison
- Neuroscience Development, Novartis Pharma AG, CH-4056 Basel, Switzerland.
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Davenport MH, Schaefer TL, Friedmann KJ, Fitzpatrick SE, Erickson CA. Pharmacotherapy for Fragile X Syndrome: Progress to Date. Drugs 2016; 76:431-45. [PMID: 26858239 DOI: 10.1007/s40265-016-0542-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
To date, no drug is approved for the treatment of Fragile X Syndrome (FXS) although many drugs are used to manage challenging behaviors from a symptomatic perspective in this population. While our understanding of FXS pathophysiology is expanding, efforts to devise targeted FXS-specific treatments have had limited success in placebo-controlled trials. Compounds aimed at rectifying excessive glutamate and deficient gamma-aminobutyric acid (GABA) neurotransmission, as well as other signaling pathways known to be affected by Fragile X Mental Retardation Protein (FMRP) are under various phases of development in FXS. With the failure of several metabotropic glutamate receptor subtype 5 (mGlur5) selective antagonists under clinical investigation, no clear single treatment appears to be greatly effective. These recent challenges call into question various aspects of clinical study design in FXS. More objective outcome measures are under development and validation. Future trials will likely be aimed at correcting multiple pathways known to be disrupted by the loss of FMRP. This review offers a brief summary of the prevalence, phenotypic characteristics, genetic causes and molecular functions of FMRP in the brain (as these have been extensively reviewed elsewhere), discusses the most recent finding in FXS drug development, and summarizes FXS trials utilizing symptomatic treatment.
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Affiliation(s)
- Matthew H Davenport
- Division of Child and Adolescent Psychiatry (MLC 4002), Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
- Department of Biomedical Engineering, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, OH, 45221, USA
| | - Tori L Schaefer
- Division of Child and Adolescent Psychiatry (MLC 4002), Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
| | - Katherine J Friedmann
- Division of Child and Adolescent Psychiatry (MLC 4002), Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA
| | | | - Craig A Erickson
- Division of Child and Adolescent Psychiatry (MLC 4002), Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229-3039, USA.
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Lin YC, Frei JA, Kilander MBC, Shen W, Blatt GJ. A Subset of Autism-Associated Genes Regulate the Structural Stability of Neurons. Front Cell Neurosci 2016; 10:263. [PMID: 27909399 PMCID: PMC5112273 DOI: 10.3389/fncel.2016.00263] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 10/28/2016] [Indexed: 12/15/2022] Open
Abstract
Autism spectrum disorder (ASD) comprises a range of neurological conditions that affect individuals’ ability to communicate and interact with others. People with ASD often exhibit marked qualitative difficulties in social interaction, communication, and behavior. Alterations in neurite arborization and dendritic spine morphology, including size, shape, and number, are hallmarks of almost all neurological conditions, including ASD. As experimental evidence emerges in recent years, it becomes clear that although there is broad heterogeneity of identified autism risk genes, many of them converge into similar cellular pathways, including those regulating neurite outgrowth, synapse formation and spine stability, and synaptic plasticity. These mechanisms together regulate the structural stability of neurons and are vulnerable targets in ASD. In this review, we discuss the current understanding of those autism risk genes that affect the structural connectivity of neurons. We sub-categorize them into (1) cytoskeletal regulators, e.g., motors and small RhoGTPase regulators; (2) adhesion molecules, e.g., cadherins, NCAM, and neurexin superfamily; (3) cell surface receptors, e.g., glutamatergic receptors and receptor tyrosine kinases; (4) signaling molecules, e.g., protein kinases and phosphatases; and (5) synaptic proteins, e.g., vesicle and scaffolding proteins. Although the roles of some of these genes in maintaining neuronal structural stability are well studied, how mutations contribute to the autism phenotype is still largely unknown. Investigating whether and how the neuronal structure and function are affected when these genes are mutated will provide insights toward developing effective interventions aimed at improving the lives of people with autism and their families.
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Affiliation(s)
- Yu-Chih Lin
- Laboratory of Neuronal Connectivity, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
| | - Jeannine A Frei
- Laboratory of Neuronal Connectivity, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
| | - Michaela B C Kilander
- Laboratory of Neuronal Connectivity, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
| | - Wenjuan Shen
- Laboratory of Neuronal Connectivity, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
| | - Gene J Blatt
- Laboratory of Autism Neurocircuitry, Program in Neuroscience, Hussman Institute for Autism, Baltimore MD, USA
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116
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Gipson CD, Olive MF. Structural and functional plasticity of dendritic spines - root or result of behavior? GENES BRAIN AND BEHAVIOR 2016; 16:101-117. [PMID: 27561549 DOI: 10.1111/gbb.12324] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/19/2016] [Accepted: 08/24/2016] [Indexed: 02/06/2023]
Abstract
Dendritic spines are multifunctional integrative units of the nervous system and are highly diverse and dynamic in nature. Both internal and external stimuli influence dendritic spine density and morphology on the order of minutes. It is clear that the structural plasticity of dendritic spines is related to changes in synaptic efficacy, learning and memory and other cognitive processes. However, it is currently unclear whether structural changes in dendritic spines are primary instigators of changes in specific behaviors, a consequence of behavioral changes, or both. In this review, we first examine the basic structure and function of dendritic spines in the brain, as well as laboratory methods to characterize and quantify morphological changes in dendritic spines. We then discuss the existing literature on the temporal and functional relationship between changes in dendritic spines in specific brain regions and changes in specific behaviors mediated by those regions. Although technological advancements have allowed us to better understand the functional relevance of structural changes in dendritic spines that are influenced by environmental stimuli, the role of spine dynamics as an underlying driver or consequence of behavior still remains elusive. We conclude that while it is likely that structural changes in dendritic spines are both instigators and results of behavioral changes, improved research tools and methods are needed to experimentally and directly manipulate spine dynamics in order to more empirically delineate the relationship between spine structure and behavior.
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Affiliation(s)
- C D Gipson
- Department of Psychology, Arizona State University, Tempe, AZ, USA
| | - M F Olive
- Department of Psychology, Arizona State University, Tempe, AZ, USA
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117
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Abbey M. Functional characterization of the several splice variants of Fmr1. RESEARCH IDEAS AND OUTCOMES 2016. [DOI: 10.3897/rio.2.e10593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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118
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Elevated ERK/p90 ribosomal S6 kinase activity underlies audiogenic seizure susceptibility in fragile X mice. Proc Natl Acad Sci U S A 2016; 113:E6290-E6297. [PMID: 27663742 DOI: 10.1073/pnas.1610812113] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Fragile X syndrome (FXS) is the most common heritable cause of intellectual disability and a leading genetic form of autism. The Fmr1 KO mouse, a model of FXS, exhibits elevated translation in the hippocampus and the cortex. ERK (extracellular signal-regulated kinase) and mTOR (mechanistic target of rapamycin) signaling regulate protein synthesis by activating downstream targets critical to translation initiation and elongation and are known to contribute to hippocampal defects in fragile X. Here we show that the effect of loss of fragile X mental retardation protein (FMRP) on these pathways is brain region specific. In contrast to the hippocampus, ERK (but not mTOR) signaling is elevated in the neocortex of fragile X mice. Phosphorylation of ribosomal protein S6, typically a downstream target of mTOR, is elevated in the neocortex, despite normal mTOR activity. This is significant in that S6 phosphorylation facilitates translation, correlates with neuronal activation, and is altered in neurodevelopmental disorders. We show that in fragile X mice, S6 is regulated by ERK via the "alternative" S6 kinase p90-ribosomal S6 kinase (RSK), as evidenced by the site of elevated phosphorylation and the finding that ERK inhibition corrects elevated RSK and S6 activity. These findings indicate that signaling networks are altered in the neocortex of fragile X mice such that S6 phosphorylation receives aberrant input from ERK/RSK. Importantly, an RSK inhibitor reduces susceptibility to audiogenic seizures in fragile X mice. Our findings identify RSK as a therapeutic target for fragile X and suggest the therapeutic potential of drugs for the treatment of FXS may vary in a brain-region-specific manner.
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119
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Tabet R, Vitale N, Moine H. Fragile X syndrome: Are signaling lipids the missing culprits? Biochimie 2016; 130:188-194. [PMID: 27597551 DOI: 10.1016/j.biochi.2016.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 09/01/2016] [Indexed: 10/21/2022]
Abstract
Fragile X syndrome (FXS) is the most common cause of inherited intellectual disability and autism. FXS results from the absence of FMRP, an RNA binding protein associated to ribosomes that influences the translation of specific mRNAs in post-synaptic compartments of neurons. The main molecular consequence of the absence of FMRP is an excessive translation of neuronal protein in several areas of the brain. This local protein synthesis deregulation is proposed to underlie the defect in synaptic plasticity responsible for FXS. Recent findings in neurons of the fragile X mouse model (Fmr1-KO) uncovered another consequence of the lack of FMRP: a deregulation of the diacylglycerol (DAG)/phosphatidic acid (PA) homeostasis. DAG and PA are two interconvertible lipids that influence membrane architecture and that act as essential signaling molecules that activate various downstream effectors, including master regulators of local protein synthesis and actin polymerization. As a consequence, DAG and PA govern a variety of cellular processes, including cell proliferation, vesicle/membrane trafficking and cytoskeletal organization. At the synapse, the level of these lipids is proposed to influence the synaptic activation status. FMRP appears as a master regulator of this neuronal process by controlling the translation of a diacylglycerol kinase enzyme that converts DAG into PA. The deregulated levels of DAG and PA caused by the absence of FMRP could represent a novel therapeutic target for the treatment of FXS.
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Affiliation(s)
- Ricardos Tabet
- Mass General Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA
| | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Intégratives, UPR3212 CNRS, Université de Strasbourg, 67084 Strasbourg, France
| | - Hervé Moine
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67084 Strasbourg, France.
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120
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Fragile X mental retardation protein knockdown in the developing Xenopus tadpole optic tectum results in enhanced feedforward inhibition and behavioral deficits. Neural Dev 2016; 11:14. [PMID: 27503008 PMCID: PMC4977860 DOI: 10.1186/s13064-016-0069-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 08/03/2016] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Fragile X Syndrome is the leading monogenetic cause of autism and most common form of intellectual disability. Previous studies have implicated changes in dendritic spine architecture as the primary result of loss of Fragile X Mental Retardation Protein (FMRP), but recent work has shown that neural proliferation is decreased and cell death is increased with either loss of FMRP or overexpression of FMRP. The purpose of this study was to investigate the effects of loss of FMRP on behavior and cellular activity. METHODS We knocked down FMRP expression using morpholino oligos in the optic tectum of Xenopus laevis tadpoles and performed a series of behavioral and electrophysiological assays. We investigated visually guided collision avoidance, schooling, and seizure propensity. Using single cell electrophysiology, we assessed intrinsic excitability and synaptic connectivity of tectal neurons. RESULTS We found that FMRP knockdown results in decreased swimming speed, reduced schooling behavior and decreased seizure severity. In single cells, we found increased inhibition relative to excitation in response to sensory input. CONCLUSIONS Our results indicate that the electrophysiological development of single cells in the absence of FMRP is largely unaffected despite the large neural proliferation defect. The changes in behavior are consistent with an increase in inhibition, which could be due to either changes in cell number or altered inhibitory drive, and indicate that FMRP can play a significant role in neural development much earlier than previously thought.
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121
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Cheng C, Lau SKM, Doering LC. Astrocyte-secreted thrombospondin-1 modulates synapse and spine defects in the fragile X mouse model. Mol Brain 2016; 9:74. [PMID: 27485117 PMCID: PMC4971702 DOI: 10.1186/s13041-016-0256-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 07/15/2016] [Indexed: 01/24/2023] Open
Abstract
Astrocytes are key participants in various aspects of brain development and function, many of which are executed via secreted proteins. Defects in astrocyte signaling are implicated in neurodevelopmental disorders characterized by abnormal neural circuitry such as Fragile X syndrome (FXS). In animal models of FXS, the loss in expression of the Fragile X mental retardation 1 protein (FMRP) from astrocytes is associated with delayed dendrite maturation and improper synapse formation; however, the effect of astrocyte-derived factors on the development of neurons is not known. Thrombospondin-1 (TSP-1) is an important astrocyte-secreted protein that is involved in the regulation of spine development and synaptogenesis. In this study, we found that cultured astrocytes isolated from an Fmr1 knockout (Fmr1 KO) mouse model of FXS displayed a significant decrease in TSP-1 protein expression compared to the wildtype (WT) astrocytes. Correspondingly, Fmr1 KO hippocampal neurons exhibited morphological deficits in dendritic spines and alterations in excitatory synapse formation following long-term culture. All spine and synaptic abnormalities were prevented in the presence of either astrocyte-conditioned media or a feeder layer derived from FMRP-expressing astrocytes, or following the application of exogenous TSP-1. Importantly, this work demonstrates the integral role of astrocyte-secreted signals in the establishment of neuronal communication and identifies soluble TSP-1 as a potential therapeutic target for Fragile X syndrome.
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Affiliation(s)
- Connie Cheng
- McMaster Integrative Neuroscience Discovery and Study Program (MINDS), McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L8, Canada.,Department of Pathology and Molecular Medicine, McMaster University, 1200 Main Street West, HSC 1R15A, Hamilton, Ontario, L8N 3Z5, Canada
| | - Sally K M Lau
- Department of Pathology and Molecular Medicine, McMaster University, 1200 Main Street West, HSC 1R15A, Hamilton, Ontario, L8N 3Z5, Canada
| | - Laurie C Doering
- McMaster Integrative Neuroscience Discovery and Study Program (MINDS), McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L8, Canada. .,Department of Pathology and Molecular Medicine, McMaster University, 1200 Main Street West, HSC 1R15A, Hamilton, Ontario, L8N 3Z5, Canada.
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Tabet R, Moutin E, Becker JAJ, Heintz D, Fouillen L, Flatter E, Krężel W, Alunni V, Koebel P, Dembélé D, Tassone F, Bardoni B, Mandel JL, Vitale N, Muller D, Le Merrer J, Moine H. Fragile X Mental Retardation Protein (FMRP) controls diacylglycerol kinase activity in neurons. Proc Natl Acad Sci U S A 2016; 113:E3619-28. [PMID: 27233938 PMCID: PMC4932937 DOI: 10.1073/pnas.1522631113] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fragile X syndrome (FXS) is caused by the absence of the Fragile X Mental Retardation Protein (FMRP) in neurons. In the mouse, the lack of FMRP is associated with an excessive translation of hundreds of neuronal proteins, notably including postsynaptic proteins. This local protein synthesis deregulation is proposed to underlie the observed defects of glutamatergic synapse maturation and function and to affect preferentially the hundreds of mRNA species that were reported to bind to FMRP. How FMRP impacts synaptic protein translation and which mRNAs are most important for the pathology remain unclear. Here we show by cross-linking immunoprecipitation in cortical neurons that FMRP is mostly associated with one unique mRNA: diacylglycerol kinase kappa (Dgkκ), a master regulator that controls the switch between diacylglycerol and phosphatidic acid signaling pathways. The absence of FMRP in neurons abolishes group 1 metabotropic glutamate receptor-dependent DGK activity combined with a loss of Dgkκ expression. The reduction of Dgkκ in neurons is sufficient to cause dendritic spine abnormalities, synaptic plasticity alterations, and behavior disorders similar to those observed in the FXS mouse model. Overexpression of Dgkκ in neurons is able to rescue the dendritic spine defects of the Fragile X Mental Retardation 1 gene KO neurons. Together, these data suggest that Dgkκ deregulation contributes to FXS pathology and support a model where FMRP, by controlling the translation of Dgkκ, indirectly controls synaptic proteins translation and membrane properties by impacting lipid signaling in dendritic spine.
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Affiliation(s)
- Ricardos Tabet
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Enora Moutin
- Department of Basic Neuroscience, University of Geneva, 1211 Geneva 4, Switzerland
| | - Jérôme A J Becker
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Dimitri Heintz
- Institut de Biologie Moléculaire des Plantes, Plateforme Métabolomique, Unité Propre de Recherche (UPR) 2357 CNRS, Université de Strasbourg, 67082 Strasbourg, France
| | - Laetitia Fouillen
- Laboratoire de Biogènese Membranaire; UMR 5200 CNRS, Plateforme Métabolome, Université de Bordeaux, 33140 Villenave D'Ornon, France
| | - Eric Flatter
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Wojciech Krężel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Violaine Alunni
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Pascale Koebel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Doulaye Dembélé
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Flora Tassone
- Medical Investigation of Neurodevelopmental Disorders Institute, University of California Davis Medical Center, Sacramento, CA 95817
| | - Barbara Bardoni
- CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology, University of Nice Sophia-Antipolis, CNRS Laboratoire International Associé (LIA) Neogenex, 06560 Valbonne, France
| | - Jean-Louis Mandel
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France; Collège de France, 75005 Paris, France
| | - Nicolas Vitale
- Institut des Neurosciences Cellulaires et Intégratives, UPR3212 CNRS, Université de Strasbourg, 67084 Strasbourg, France
| | - Dominique Muller
- Department of Basic Neuroscience, University of Geneva, 1211 Geneva 4, Switzerland
| | - Julie Le Merrer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France
| | - Hervé Moine
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67404 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67404 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France;
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123
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Kashima R, Roy S, Ascano M, Martinez-Cerdeno V, Ariza-Torres J, Kim S, Louie J, Lu Y, Leyton P, Bloch KD, Kornberg TB, Hagerman PJ, Hagerman R, Lagna G, Hata A. Augmented noncanonical BMP type II receptor signaling mediates the synaptic abnormality of fragile X syndrome. Sci Signal 2016; 9:ra58. [PMID: 27273096 DOI: 10.1126/scisignal.aaf6060] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Epigenetic silencing of fragile X mental retardation 1 (FMR1) causes fragile X syndrome (FXS), a common inherited form of intellectual disability and autism. FXS correlates with abnormal synapse and dendritic spine development, but the molecular link between the absence of the FMR1 product FMRP, an RNA binding protein, and the neuropathology is unclear. We found that the messenger RNA encoding bone morphogenetic protein type II receptor (BMPR2) is a target of FMRP. Depletion of FMRP increased BMPR2 abundance, especially that of the full-length isoform that bound and activated LIM domain kinase 1 (LIMK1), a component of the noncanonical BMP signal transduction pathway that stimulates actin reorganization to promote neurite outgrowth and synapse formation. Heterozygosity for BMPR2 rescued the morphological abnormalities in neurons both in Drosophila and in mouse models of FXS, as did the postnatal pharmacological inhibition of LIMK1 activity. Compared with postmortem prefrontal cortex tissue from healthy subjects, the amount of full-length BMPR2 and of a marker of LIMK1 activity was increased in this brain region from FXS patients. These findings suggest that increased BMPR2 signal transduction is linked to FXS and that the BMPR2-LIMK1 pathway is a putative therapeutic target in patients with FXS and possibly other forms of autism.
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Affiliation(s)
- Risa Kashima
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Sougata Roy
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Manuel Ascano
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Veronica Martinez-Cerdeno
- Institute for Pediatric Regenerative Medicine, Department of Pathology, University of California, Davis, Davis, CA 95817, USA. MIND (Medical Investigation of Neurodevelopmental Disorders) Institute, University of California, Davis, Davis, CA 95817, USA
| | - Jeanelle Ariza-Torres
- Institute for Pediatric Regenerative Medicine, Department of Pathology, University of California, Davis, Davis, CA 95817, USA
| | - Sunghwan Kim
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Justin Louie
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Yao Lu
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Patricio Leyton
- Anesthesia and Critical Care, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Kenneth D Bloch
- Anesthesia and Critical Care, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Thomas B Kornberg
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Paul J Hagerman
- Department of Biochemistry and Molecular Medicine, University of California, Davis, Davis, CA 95817, USA
| | - Randi Hagerman
- MIND (Medical Investigation of Neurodevelopmental Disorders) Institute, University of California, Davis, Davis, CA 95817, USA
| | - Giorgio Lagna
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Akiko Hata
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94143, USA.
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Abstract
Fragile X syndrome is the most common inherited form of intellectual disability and results from a loss of function of the translational repressor FMRP. In this issue of Science Signaling, Kashima et al find that FMRP binds to and represses a specific isoform of BMPR2, a type II bone morphogenetic protein (BMP) receptor. Reducing signaling through this BMP pathway reverses neuroanatomical defects observed in fragile X models.
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Affiliation(s)
- Heather T Broihier
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA.
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125
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Hippocampal neuronal subtypes develop abnormal dendritic arbors in the presence of Fragile X astrocytes. Neuroscience 2016; 324:202-17. [DOI: 10.1016/j.neuroscience.2016.03.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 02/02/2016] [Accepted: 03/04/2016] [Indexed: 12/18/2022]
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126
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Meziane H, Khelfaoui M, Morello N, Hiba B, Calcagno E, Reibel-Foisset S, Selloum M, Chelly J, Humeau Y, Riet F, Zanni G, Herault Y, Bienvenu T, Giustetto M, Billuart P. Fasudil treatment in adult reverses behavioural changes and brain ventricular enlargement in Oligophrenin-1 mouse model of intellectual disability. Hum Mol Genet 2016; 25:2314-2323. [PMID: 27146843 DOI: 10.1093/hmg/ddw102] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 03/17/2016] [Indexed: 01/09/2023] Open
Abstract
Loss of function mutations in human Oligophrenin1 (OPHN1) gene are responsible for syndromic intellectual disability (ID) associated with cerebellar hypoplasia and cerebral ventricles enlargement. Functional studies in rodent models suggest that OPHN1 linked ID is a consequence of abnormal synaptic transmission and shares common pathophysiological mechanisms with other cognitive disorders. Variants of this gene have been also identified in autism spectrum disorder and schizophrenia. The advanced understanding of the mechanisms underlying OPHN1-related ID, allowed us to develop a therapeutic approach targeting the Ras homolog gene family, member A (RHOA) signalling pathway and repurpose Fasudil- a well-tolerated Rho Kinase (ROCK) and Protein Kinase A (PKA) inhibitor- as a treatment of ID. We have previously shown ex-vivo its beneficial effect on synaptic transmission and plasticity in a mouse model of the OPHN1 loss of function. Here, we report that chronic treatment in adult mouse with Fasudil, is able to counteract vertical and horizontal hyperactivities, restores recognition memory and limits the brain ventricular dilatation observed in Ophn1-/y However, deficits in working and spatial memories are partially or not rescued by the treatment. These results highlight the potential of Fasudil treatment in synaptopathies and also the need for multiple therapeutic approaches especially in adult where brain plasticity is reduced.
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Affiliation(s)
- Hamid Meziane
- PHENOMIN, Institut Clinique de la Souris, ICS; GIE CERBM, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, UMR7104, INSERM, U964, University of Strasbourg, F-67404 Illkirch-Graffenstaden, France
| | - Malik Khelfaoui
- Institut Cochin, INSERM U1016, CNRS UMR8104, Paris Descartes University, Paris, 75014, France Institut interdisciplinaire de neuroscience, CNRS UMR5297, University of Bordeaux, Bordeaux, 33077, France
| | - Noemi Morello
- University of Torino, Department of Neuroscience « Rita Levi Montalcini », National Institute of Neuroscience-Italy, Torino, 10126, Italy
| | - Bassem Hiba
- Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS, Université de Bordeaux, 33077, Bordeaux, France
| | - Eleonora Calcagno
- University of Torino, Department of Neuroscience « Rita Levi Montalcini », National Institute of Neuroscience-Italy, Torino, 10126, Italy
| | | | - Mohammed Selloum
- PHENOMIN, Institut Clinique de la Souris, ICS; GIE CERBM, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, UMR7104, INSERM, U964, University of Strasbourg, F-67404 Illkirch-Graffenstaden, France
| | - Jamel Chelly
- PHENOMIN, Institut Clinique de la Souris, ICS; GIE CERBM, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, UMR7104, INSERM, U964, University of Strasbourg, F-67404 Illkirch-Graffenstaden, France Institut Cochin, INSERM U1016, CNRS UMR8104, Paris Descartes University, Paris, 75014, France
| | - Yann Humeau
- Institut interdisciplinaire de neuroscience, CNRS UMR5297, University of Bordeaux, Bordeaux, 33077, France
| | - Fabrice Riet
- PHENOMIN, Institut Clinique de la Souris, ICS; GIE CERBM, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, UMR7104, INSERM, U964, University of Strasbourg, F-67404 Illkirch-Graffenstaden, France
| | - Ginevra Zanni
- Department of Neurosciences, Laboratory of Molecular Medicine, Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesù Children's Hospital, IRCCS, 00165, Rome, Italy
| | - Yann Herault
- PHENOMIN, Institut Clinique de la Souris, ICS; GIE CERBM, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, UMR7104, INSERM, U964, University of Strasbourg, F-67404 Illkirch-Graffenstaden, France
| | - Thierry Bienvenu
- Institut Cochin, INSERM U1016, CNRS UMR8104, Paris Descartes University, Paris, 75014, France
| | - Maurizio Giustetto
- University of Torino, Department of Neuroscience « Rita Levi Montalcini », National Institute of Neuroscience-Italy, Torino, 10126, Italy
| | - Pierre Billuart
- Institut Cochin, INSERM U1016, CNRS UMR8104, Paris Descartes University, Paris, 75014, France
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127
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Synaptic Plasticity, a Prominent Contributor to the Anxiety in Fragile X Syndrome. Neural Plast 2016; 2016:9353929. [PMID: 27239350 PMCID: PMC4864533 DOI: 10.1155/2016/9353929] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 04/04/2016] [Indexed: 01/03/2023] Open
Abstract
Fragile X syndrome (FXS) is an inheritable neuropsychological disease caused by expansion of the CGG trinucleotide repeat affecting the fmr1 gene on X chromosome, resulting in silence of the fmr1 gene and failed expression of FMRP. Patients with FXS suffer from cognitive impairment, sensory integration deficits, learning disability, anxiety, autistic traits, and so forth. Specifically, the morbidity of anxiety in FXS individuals remains high from childhood to adulthood. By and large, it is common that the change of brain plasticity plays a key role in the progression of disease. But for now, most studies excessively emphasized the one-sided factor on the change of synaptic plasticity participating in the generation of anxiety during the development of FXS. Here we proposed an integrated concept to acquire better recognition about the details of this process.
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128
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Vafadari B, Salamian A, Kaczmarek L. MMP-9 in translation: from molecule to brain physiology, pathology, and therapy. J Neurochem 2016; 139 Suppl 2:91-114. [PMID: 26525923 DOI: 10.1111/jnc.13415] [Citation(s) in RCA: 286] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/13/2015] [Accepted: 10/19/2015] [Indexed: 12/11/2022]
Abstract
Matrix metalloproteinase-9 (MMP-9) is a member of the metzincin family of mostly extracellularly operating proteases. Despite the fact that all of these enzymes might be target promiscuous, with largely overlapping catalogs of potential substrates, MMP-9 has recently emerged as a major and apparently unique player in brain physiology and pathology. The specificity of MMP-9 may arise from its very local and time-restricted actions, even when released in the brain from cells of various types, including neurons, glia, and leukocytes. In fact, the quantity of MMP-9 is very low in the naive brain, but it is markedly activated at the levels of enzymatic activity, protein abundance, and gene expression following various physiological stimuli and pathological insults. Neuronal MMP-9 participates in synaptic plasticity by controlling the shape of dendritic spines and function of excitatory synapses, thus playing a pivotal role in learning, memory, and cortical plasticity. When improperly unleashed, MMP-9 contributes to a large variety of brain disorders, including epilepsy, schizophrenia, autism spectrum disorder, brain injury, stroke, neurodegeneration, pain, brain tumors, etc. The foremost mechanism of action of MMP-9 in brain disorders appears to be its involvement in immune/inflammation responses that are related to the enzyme's ability to process and activate various cytokines and chemokines, as well as its contribution to blood-brain barrier disruption, facilitating the extravasation of leukocytes into brain parenchyma. However, another emerging possibility (i.e., the control of MMP-9 over synaptic plasticity) should not be neglected. The translational potential of MMP-9 has already been recognized in both the diagnosis and treatment domains. The most striking translational aspect may be the discovery of MMP-9 up-regulation in a mouse model of Fragile X syndrome, quickly followed by human studies and promising clinical trials that have sought to inhibit MMP-9. With regard to diagnosis, suggestions have been made to use MMP-9 alone or combined with tissue inhibitor of matrix metalloproteinase-1 or brain-derived neurotrophic factor as disease biomarkers. MMP-9, through cleavage of specific target proteins, plays a major role in synaptic plasticity and neuroinflammation, and by those virtues contributes to brain physiology and a host of neurological and psychiatric disorders. This article is part of the 60th Anniversary special issue.
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129
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Neuronal profilins in health and disease: Relevance for spine plasticity and Fragile X syndrome. Proc Natl Acad Sci U S A 2016; 113:3365-70. [PMID: 26951674 DOI: 10.1073/pnas.1516697113] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Learning and memory, to a large extent, depend on functional changes at synapses. Actin dynamics orchestrate the formation of synapses, as well as their stabilization, and the ability to undergo plastic changes. Hence, profilins are of key interest as they bind to G-actin and enhance actin polymerization. However, profilins also compete with actin nucleators, thereby restricting filament formation. Here, we provide evidence that the two brain isoforms, profilin1 (PFN1) and PFN2a, regulate spine actin dynamics in an opposing fashion, and that whereas both profilins are needed during synaptogenesis, only PFN2a is crucial for adult spine plasticity. This finding suggests that PFN1 is the juvenile isoform important during development, whereas PFN2a is mandatory for spine stability and plasticity in mature neurons. In line with this finding, only PFN1 levels are altered in the mouse model of the developmental neurological disorder Fragile X syndrome. This finding is of high relevance because Fragile X syndrome is the most common monogenetic cause for autism spectrum disorder. Indeed, the expression of recombinant profilins rescued the impairment in spinogenesis, a hallmark in Fragile X syndrome, thereby linking the regulation of actin dynamics to synapse development and possible dysfunction.
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130
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Functional magnetic resonance imaging in awake transgenic fragile X rats: evidence of dysregulation in reward processing in the mesolimbic/habenular neural circuit. Transl Psychiatry 2016; 6:e763. [PMID: 27003189 PMCID: PMC4872441 DOI: 10.1038/tp.2016.15] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 12/06/2015] [Accepted: 01/19/2016] [Indexed: 01/19/2023] Open
Abstract
Anxiety and social deficits, often involving communication impairment, are fundamental clinical features of fragile X syndrome. There is growing evidence that dysregulation in reward processing is a contributing factor to the social deficits observed in many psychiatric disorders. Hence, we hypothesized that transgenic fragile X mental retardation 1 gene (fmr1) KO (FX) rats would display alterations in reward processing. To this end, awake control and FX rats were imaged for changes in blood oxygen level dependent (BOLD) signal intensity in response to the odor of almond, a stimulus to elicit the innate reward response. Subjects were 'odor naive' to this evolutionarily conserved stimulus. The resulting changes in brain activity were registered to a three-dimensional segmented, annotated rat atlas delineating 171 brain regions. Both wild-type (WT) and FX rats showed robust brain activation to a rewarding almond odor, though FX rats showed an altered temporal pattern and tended to have a higher number of voxels with negative BOLD signal change from baseline. This pattern of greater negative BOLD was especially apparent in the Papez circuit, critical to emotional processing and the mesolimbic/habenular reward circuit. WT rats showed greater positive BOLD response in the supramammillary area, whereas FX rats showed greater positive BOLD response in the dorsal lateral striatum, and greater negative BOLD response in the retrosplenial cortices, the core of the accumbens and the lateral preoptic area. When tested in a freely behaving odor-investigation paradigm, FX rats failed to show the preference for almond odor which typifies WT rats. However, FX rats showed investigation profiles similar to WT when presented with social odors. These data speak to an altered processing of this highly salient novel odor in the FX phenotype and lend further support to the notion that altered reward systems in the brain may contribute to fragile X syndrome symptomology.
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131
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LaCrosse AL, Taylor SB, Nemirovsky NE, Gass JT, Olive MF. mGluR5 Positive and Negative Allosteric Modulators Differentially Affect Dendritic Spine Density and Morphology in the Prefrontal Cortex. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2016; 14:476-85. [PMID: 25921744 DOI: 10.2174/1871527314666150429112849] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 01/17/2015] [Accepted: 01/19/2015] [Indexed: 12/31/2022]
Abstract
Positive and negative allosteric modulators (PAMs and NAMs, respectively) of type 5 metabotropic glutamate receptors (mGluR5) are currently being investigated as novel treatments for neuropsychiatric diseases including drug addiction, schizophrenia, and Fragile X syndrome. However, only a handful of studies have examined the effects of mGluR5 PAMs or NAMs on the structural plasticity of dendritic spines in otherwise naïve animals, particularly in brain regions mediating executive function. In the present study, we assessed dendritic spine density and morphology in pyramidal cells of the medial prefrontal cortex (mPFC) after repeated administration of either the prototypical mGluR5 PAM 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5- yl)benzamide (CDPPB, 20 mg/kg), the clinically utilized mGluR5 NAM 1-(3-chlorophenyl)-3-(3-methyl-5-oxo-4Himidazol- 2-yl)urea (fenobam, 20 mg/kg), or vehicle in male Sprague-Dawley rats. Following once daily treatment for 10 consecutive days, coronal brain sections containing the mPFC underwent diolistic labeling and 3D image analysis of dendritic spines. Compared to vehicle treated animals, rats administered fenobam exhibited significant increases in dendritic spine density and the overall frequency of spines with small (<0.2 μm) head diameters, decreases in frequency of spines with medium (0.2-0.4 μm) head diameters, and had no changes in frequency of spines with large head diameters (>0.4 μm). Administration of CDPPB had no discernable effects on dendritic spine density or morphology, and neither CDPPB nor fenobam had any effect on spine length or volume. We conclude that mGluR5 PAMs and NAMs differentially affect mPFC dendritic spine structural plasticity in otherwise naïve animals, and additional studies assessing their effects in combination with cognitive or behavioral tasks are needed.
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Affiliation(s)
| | | | | | | | - Michael F Olive
- Department of Psychology, Arizona State University, PO Box 871104, Tempe, AZ 85287, USA.
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132
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Monogenic mouse models of autism spectrum disorders: Common mechanisms and missing links. Neuroscience 2015; 321:3-23. [PMID: 26733386 DOI: 10.1016/j.neuroscience.2015.12.040] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 11/30/2015] [Accepted: 12/22/2015] [Indexed: 01/16/2023]
Abstract
Autism spectrum disorders (ASDs) present unique challenges in the fields of genetics and neurobiology because of the clinical and molecular heterogeneity underlying these disorders. Genetic mutations found in ASD patients provide opportunities to dissect the molecular and circuit mechanisms underlying autistic behaviors using animal models. Ongoing studies of genetically modified models have offered critical insight into possible common mechanisms arising from different mutations, but links between molecular abnormalities and behavioral phenotypes remain elusive. The challenges encountered in modeling autism in mice demand a new analytic paradigm that integrates behavioral assessment with circuit-level analysis in genetically modified models with strong construct validity.
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133
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Abstract
Fragile X syndrome (FXS) results from a genetic mutation in a single gene yet produces a phenotypically complex disorder with a range of neurological and psychiatric problems. Efforts to decipher how perturbations in signaling pathways lead to the myriad alterations in synaptic and cellular functions have provided insights into the molecular underpinnings of this disorder. From this large body of data, the theme of circuit hyperexcitability has emerged as a potential explanation for many of the neurological and psychiatric symptoms in FXS. The mechanisms for hyperexcitability range from alterations in the expression or activity of ion channels to changes in neurotransmitters and receptors. Contributions of these processes are often brain region and cell type specific, resulting in complex effects on circuit function that manifest as altered excitability. Here, we review the current state of knowledge of the molecular, synaptic, and circuit-level mechanisms underlying hyperexcitability and their contributions to the FXS phenotypes.
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134
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Abstract
TOR (target of rapamycin) and its mammalian ortholog mTOR have been discovered in an effort to understand the mechanisms of action of the immunosuppressant drug rapamycin extracted from a bacterium of the Easter Island (Rapa Nui) soil. mTOR is a serine/threonine kinase found in two functionally distinct complexes, mTORC1 and mTORC2, which are differentially regulated by a great number of nutrients such as glucose and amino acids, energy (oxygen and ATP/AMP content), growth factors, hormones, and neurotransmitters. mTOR controls many basic cellular functions such as protein synthesis, energy metabolism, cell size, lipid metabolism, autophagy, mitochondria, and lysosome biogenesis. In addition, mTOR-controlled signaling pathways regulate many integrated physiological functions of the nervous system including neuronal development, synaptic plasticity, memory storage, and cognition. Thus it is not surprising that deregulation of mTOR signaling is associated with many neurological and psychiatric disorders. Preclinical and preliminary clinical studies indicate that inhibition of mTORC1 can be beneficial for some pathological conditions such as epilepsy, cognitive impairment, and brain tumors, whereas stimulation of mTORC1 (direct or indirect) can be beneficial for other pathologies such as depression or axonal growth and regeneration.
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Affiliation(s)
- Joël Bockaert
- Centre National de la Recherche Scientifique, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier, France; Institut National de la Santé et de la Recherche Médicale U1191, Montpellier, France; and Université de Montpellier, UMR-5203, Montpellier, France
| | - Philippe Marin
- Centre National de la Recherche Scientifique, UMR-5203, Institut de Génomique Fonctionnelle, Montpellier, France; Institut National de la Santé et de la Recherche Médicale U1191, Montpellier, France; and Université de Montpellier, UMR-5203, Montpellier, France
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135
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Subramanian M, Timmerman CK, Schwartz JL, Pham DL, Meffert MK. Characterizing autism spectrum disorders by key biochemical pathways. Front Neurosci 2015; 9:313. [PMID: 26483618 PMCID: PMC4586332 DOI: 10.3389/fnins.2015.00313] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 08/20/2015] [Indexed: 12/29/2022] Open
Abstract
The genetic and phenotypic heterogeneity of autism spectrum disorders (ASD) presents a substantial challenge for diagnosis, classification, research, and treatment. Investigations into the underlying molecular etiology of ASD have often yielded mixed and at times opposing findings. Defining the molecular and biochemical underpinnings of heterogeneity in ASD is crucial to our understanding of the pathophysiological development of the disorder, and has the potential to assist in diagnosis and the rational design of clinical trials. In this review, we propose that genetically diverse forms of ASD may be usefully parsed into entities resulting from converse patterns of growth regulation at the molecular level, which lead to the correlates of general synaptic and neural overgrowth or undergrowth. Abnormal brain growth during development is a characteristic feature that has been observed both in children with autism and in mouse models of autism. We review evidence from syndromic and non-syndromic ASD to suggest that entities currently classified as autism may fundamentally differ by underlying pro- or anti-growth abnormalities in key biochemical pathways, giving rise to either excessive or reduced synaptic connectivity in affected brain regions. We posit that this classification strategy has the potential not only to aid research efforts, but also to ultimately facilitate early diagnosis and direct appropriate therapeutic interventions.
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Affiliation(s)
- Megha Subramanian
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Christina K Timmerman
- Department of Biological Chemistry, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Joshua L Schwartz
- Department of Biological Chemistry, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Daniel L Pham
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Mollie K Meffert
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine Baltimore, MD, USA ; Department of Biological Chemistry, Johns Hopkins University School of Medicine Baltimore, MD, USA
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136
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Natarajan R, Barber K, Buckley A, Cho P, Egbejimi A, Wairkar YP. Tricornered Kinase Regulates Synapse Development by Regulating the Levels of Wiskott-Aldrich Syndrome Protein. PLoS One 2015; 10:e0138188. [PMID: 26393506 PMCID: PMC4578898 DOI: 10.1371/journal.pone.0138188] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 08/26/2015] [Indexed: 11/19/2022] Open
Abstract
Precise regulation of synapses during development is essential to ensure accurate neural connectivity and function of nervous system. Many signaling pathways, including the mTOR (mechanical Target of Rapamycin) pathway operate in neurons to maintain genetically determined number of synapses during development. mTOR, a kinase, is shared between two functionally distinct multi-protein complexes- mTORC1 and mTORC2, that act downstream of Tuberous Sclerosis Complex (TSC). We and others have suggested an important role for TSC in synapse development at the Drosophila neuromuscular junction (NMJ) synapses. In addition, our data suggested that the regulation of the NMJ synapse numbers in Drosophila largely depends on signaling via mTORC2. In the present study, we further this observation by identifying Tricornered (Trc) kinase, a serine/threonine kinase as a likely mediator of TSC signaling. trc genetically interacts with Tsc2 to regulate the number of synapses. In addition, Tsc2 and trc mutants exhibit a dramatic reduction in synaptic levels of WASP, an important regulator of actin polymerization. We show that Trc regulates the WASP levels largely, by regulating the transcription of WASP. Finally, we show that overexpression of WASP (Wiskott-Aldrich Syndrome Protein) in trc mutants can suppress the increase in the number of synapses observed in trc mutants, suggesting that WASP regulates synapses downstream of Trc. Thus, our data provide a novel insight into how Trc may regulate the genetic program that controls the number of synapses during development.
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Affiliation(s)
- Rajalaxmi Natarajan
- Department of Neurology and Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Kara Barber
- Neuroscience Graduate Program, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Amanda Buckley
- Department of Neurology and Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Phillip Cho
- Summer Undergraduate Research Program, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Anuoluwapo Egbejimi
- Department of Neurology, University of Texas Medical Branch, Galveston, Texas, United States of America
- Neuroscience Graduate Program, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Yogesh P. Wairkar
- Department of Neurology and Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
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137
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Fmr1 deficiency promotes age-dependent alterations in the cortical synaptic proteome. Proc Natl Acad Sci U S A 2015; 112:E4697-706. [PMID: 26307763 DOI: 10.1073/pnas.1502258112] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Fragile X syndrome (FXS) is an X-linked neurodevelopmental disorder characterized by severe intellectual disability and other symptoms including autism. Although caused by the silencing of a single gene, Fmr1 (fragile X mental retardation 1), the complexity of FXS pathogenesis is amplified because the encoded protein, FMRP, regulates the activity-dependent translation of numerous mRNAs. Although the mRNAs that associate with FMRP have been extensively studied, little is known regarding the proteins whose expression levels are altered, directly or indirectly, by loss of FMRP during brain development. Here we systematically measured protein expression in neocortical synaptic fractions from Fmr1 knockout (KO) and wild-type (WT) mice at both adolescent and adult stages. Although hundreds of proteins are up-regulated in the absence of FMRP in young mice, this up-regulation is largely diminished in adulthood. Up-regulated proteins included previously unidentified as well as known targets involved in synapse formation and function and brain development and others linked to intellectual disability and autism. Comparison with putative FMRP target mRNAs and autism susceptibility genes revealed substantial overlap, consistent with the idea that the autism endophenotype of FXS is due to a "multiple hit" effect of FMRP loss, particularly within the PSD95 interactome. Through studies of de novo protein synthesis in primary cortical neurons from KO and WT mice, we found that neurons lacking FMRP produce nascent proteins at higher rates, many of which are synaptic proteins and encoded by FMRP target mRNAs. Our results provide a greatly expanded view of protein changes in FXS and identify age-dependent effects of FMRP in shaping the neuronal proteome.
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138
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Coordinated Spine Pruning and Maturation Mediated by Inter-Spine Competition for Cadherin/Catenin Complexes. Cell 2015; 162:808-22. [PMID: 26255771 DOI: 10.1016/j.cell.2015.07.018] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 04/11/2015] [Accepted: 06/13/2015] [Indexed: 02/04/2023]
Abstract
Dendritic spines are postsynaptic compartments of excitatory synapses that undergo dynamic changes during development, including rapid spinogenesis in early postnatal life and significant pruning during adolescence. Spine pruning defects have been implicated in developmental neurological disorders such as autism, yet much remains to be uncovered regarding its molecular mechanism. Here, we show that spine pruning and maturation in the mouse somatosensory cortex are coordinated via the cadherin/catenin cell adhesion complex and bidrectionally regulated by sensory experience. We further demonstrate that locally enhancing cadherin/catenin-dependent adhesion or photo-stimulating a contacting channelrhodopsin-expressing axon stabilized the manipulated spine and eliminated its neighbors, an effect requiring cadherin/catenin-dependent adhesion. Importantly, we show that differential cadherin/catenin-dependent adhesion between neighboring spines biased spine fate in vivo. These results suggest that activity-induced inter-spine competition for β-catenin provides specificity for concurrent spine maturation and elimination and thus is critical for the molecular control of spine pruning during neural circuit refinement.
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139
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Motanis H, Buonomano D. Delayed in vitro development of Up states but normal network plasticity in Fragile X circuits. Eur J Neurosci 2015; 42:2312-21. [PMID: 26138886 DOI: 10.1111/ejn.13010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 06/26/2015] [Accepted: 06/29/2015] [Indexed: 11/30/2022]
Abstract
A broad range of neurophysiological phenotypes have been reported since the generation of the first mouse model of Fragile X syndrome (FXS). However, it remains unclear which phenotypes are causally related to the cognitive deficits associated with FXS. Indeed, because many of these phenotypes are known to be modulated by experience, a confounding factor in the interpretation of many studies is whether some phenotypes are an indirect consequence of abnormal development and experience. To help diminish this confound we first conducted an in vitro developmental study of spontaneous neural dynamics in cortical organotypic cultures. A significant developmental increase in network activity and Up states was observed in both wild-type and Fmr1(-/y) circuits, along with a specific developmental delay in the emergence of Up states in knockout circuits. To determine whether Up state regulation is generally impaired in FXS circuits, we examined Up state plasticity using chronic optogenetic stimulation. Wild-type and Fmr1(-/y) stimulated circuits exhibited a significant decrease in overall spontaneous activity including Up state frequency; however, no significant effect of genotype was observed. These results demonstrate that developmental delays characteristic of FXS are recapitulated during in vitro development, and that Up state abnormalities are probably a direct consequence of the disease, and not an indirect consequence of abnormal experience. However, the fact that Fmr1(-/y) circuits exhibited normal homeostatic modulation of Up states suggests that these plasticity mechanisms are largely intact, and that some of the previously reported plasticity deficits could reflect abnormal experience or the engagement of compensatory mechanisms.
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Affiliation(s)
- Helen Motanis
- Departments of Neurobiology and Psychology, Integrative Center for Learning and Memory, University of California, 695 Young Drive, Gonda, Los Angeles, CA, 90095, USA
| | - Dean Buonomano
- Departments of Neurobiology and Psychology, Integrative Center for Learning and Memory, University of California, 695 Young Drive, Gonda, Los Angeles, CA, 90095, USA
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140
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Till SM, Asiminas A, Jackson AD, Katsanevaki D, Barnes SA, Osterweil EK, Bear MF, Chattarji S, Wood ER, Wyllie DJA, Kind PC. Conserved hippocampal cellular pathophysiology but distinct behavioural deficits in a new rat model of FXS. Hum Mol Genet 2015; 24:5977-84. [PMID: 26243794 PMCID: PMC4599667 DOI: 10.1093/hmg/ddv299] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 07/21/2015] [Indexed: 11/17/2022] Open
Abstract
Recent advances in techniques for manipulating genomes have allowed the generation of transgenic animals other than mice. These new models enable cross-mammalian comparison of neurological disease from core cellular pathophysiology to circuit and behavioural endophenotypes. Moreover they will enable us to directly test whether common cellular dysfunction or behavioural outcomes of a genetic mutation are more conserved across species. Using a new rat model of Fragile X Syndrome, we report that Fmr1 knockout (KO) rats exhibit elevated basal protein synthesis and an increase in mGluR-dependent long-term depression in CA1 of the hippocampus that is independent of new protein synthesis. These defects in plasticity are accompanied by an increase in dendritic spine density selectively in apical dendrites and subtle changes in dendritic spine morphology of CA1 pyramidal neurons. Behaviourally, Fmr1 KO rats show deficits in hippocampal-dependent, but not hippocampal-independent, forms of associative recognition memory indicating that the loss of fragile X mental retardation protein (FMRP) causes defects in episodic-like memory. In contrast to previous reports from mice, Fmr1 KO rats show no deficits in spatial reference memory reversal learning. One-trial spatial learning in a delayed matching to place water maze task was also not affected by the loss of FMRP in rats. This is the first evidence for conservation across mammalian species of cellular and physiological hippocampal phenotypes associated with the loss of FMRP. Furthermore, while key cellular phenotypes are conserved they manifest in distinct behavioural dysfunction. Finally, our data reveal novel information about the selective role of FMRP in hippocampus-dependent associative memory.
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Affiliation(s)
- Sally M Till
- Patrick Wild Centre, The University of Edinburgh, Edinburgh EH8 9XD, UK, Centre for Integrative Physiology, The University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Antonis Asiminas
- Patrick Wild Centre, The University of Edinburgh, Edinburgh EH8 9XD, UK, Centre for Cognitive and Neural Systems, The University of Edinburgh, Edinburgh EH8 9JZ, UK
| | - Adam D Jackson
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh EH8 9XD, UK, Centre for Brain Development and Repair, The Institute for Stem Cell Biology and Regenerative Medicine, Bangalore 560065, India
| | - Danai Katsanevaki
- Patrick Wild Centre, The University of Edinburgh, Edinburgh EH8 9XD, UK, Centre for Integrative Physiology, The University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Stephanie A Barnes
- Patrick Wild Centre, The University of Edinburgh, Edinburgh EH8 9XD, UK, Centre for Integrative Physiology, The University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Emily K Osterweil
- Patrick Wild Centre, The University of Edinburgh, Edinburgh EH8 9XD, UK, Centre for Integrative Physiology, The University of Edinburgh, Edinburgh EH8 9XD, UK, Department of Brain and Cognitive Sciences, Howard Hughes Medical Institute, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge MA 02139, USA and
| | - Mark F Bear
- Department of Brain and Cognitive Sciences, Howard Hughes Medical Institute, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge MA 02139, USA and
| | - Sumantra Chattarji
- Patrick Wild Centre, The University of Edinburgh, Edinburgh EH8 9XD, UK, Centre for Brain Development and Repair, The Institute for Stem Cell Biology and Regenerative Medicine, Bangalore 560065, India, National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore 560065, India
| | - Emma R Wood
- Patrick Wild Centre, The University of Edinburgh, Edinburgh EH8 9XD, UK, Centre for Cognitive and Neural Systems, The University of Edinburgh, Edinburgh EH8 9JZ, UK
| | - David J A Wyllie
- Patrick Wild Centre, The University of Edinburgh, Edinburgh EH8 9XD, UK, Centre for Integrative Physiology, The University of Edinburgh, Edinburgh EH8 9XD, UK, Centre for Brain Development and Repair, The Institute for Stem Cell Biology and Regenerative Medicine, Bangalore 560065, India
| | - Peter C Kind
- Patrick Wild Centre, The University of Edinburgh, Edinburgh EH8 9XD, UK, Centre for Integrative Physiology, The University of Edinburgh, Edinburgh EH8 9XD, UK, Centre for Brain Development and Repair, The Institute for Stem Cell Biology and Regenerative Medicine, Bangalore 560065, India,
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141
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Single-Molecule Imaging of PSD-95 mRNA Translation in Dendrites and Its Dysregulation in a Mouse Model of Fragile X Syndrome. J Neurosci 2015; 35:7116-30. [PMID: 25948262 DOI: 10.1523/jneurosci.2802-14.2015] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Fragile X syndrome (FXS) is caused by the loss of the fragile X mental retardation protein (FMRP), an RNA binding protein that regulates translation of numerous target mRNAs, some of which are dendritically localized. Our previous biochemical studies using synaptoneurosomes demonstrate a role for FMRP and miR-125a in regulating the translation of PSD-95 mRNA. However, the local translation of PSD-95 mRNA within dendrites and spines, as well as the roles of FMRP or miR-125a, have not been directly studied. Herein, local synthesis of a Venus-PSD-95 fusion protein was directly visualized in dendrites and spines using single-molecule imaging of a diffusion-restricted Venus-PSD-95 reporter under control of the PSD-95 3'UTR. The basal translation rates of Venus-PSD-95 mRNA was increased in cultured hippocampal neurons from Fmr1 KO mice compared with WT neurons, which correlated with a transient elevation of endogenous PSD-95 within dendrites. Following mGluR stimulation with (S)-3,5-dihydroxyphenylglycine, the rate of Venus-PSD-95 mRNA translation increased rapidly in dendrites of WT hippocampal neurons, but not in those of Fmr1 KO neurons or when the binding site of miR125a, previously shown to bind PSD-95 3'UTR, was mutated. This study provides direct support for the hypothesis that local translation within dendrites and spines is dysregulated in FXS. Impairments in the regulated local synthesis of PSD-95, a critical regulator of synaptic structure and function, may affect the spatiotemporal control of PSD-95 levels and affect dendritic spine development and synaptic plasticity in FXS.
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142
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Early social enrichment rescues adult behavioral and brain abnormalities in a mouse model of fragile X syndrome. Neuropsychopharmacology 2015; 40:1113-22. [PMID: 25348604 PMCID: PMC4367453 DOI: 10.1038/npp.2014.291] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/16/2014] [Accepted: 09/23/2014] [Indexed: 01/10/2023]
Abstract
Converging lines of evidence support the use of environmental stimulation to ameliorate the symptoms of a variety of neurodevelopmental disorders. Applying these interventions at very early ages is critical to achieve a marked reduction of the pathological phenotypes. Here we evaluated the impact of early social enrichment in Fmr1-KO mice, a genetic mouse model of fragile X syndrome (FXS), a major developmental disorder and the most frequent monogenic cause of autism. Enrichment was achieved by providing male KO pups and their WT littermates with enhanced social stimulation, housing them from birth until weaning with the mother and an additional nonlactating female. At adulthood they were tested for locomotor, social, and cognitive abilities; furthermore, dendritic alterations were assessed in the hippocampus and amygdala, two brain regions known to be involved in the control of the examined behaviors and affected by spine pathology in Fmr1-KOs. Enrichment rescued the behavioral FXS-like deficits displayed in adulthood by Fmr1-KO mice, that is, hyperactivity, reduced social interactions, and cognitive deficits. Early social enrichment also eliminated the abnormalities shown by adult KO mice in the morphology of hippocampal and amygdala dendritic spines, namely an enhanced density of immature vs mature types. Importantly, enrichment did not induce neurobehavioral changes in WT mice, thus supporting specific effects on FXS-like pathology. These findings show that early environmental stimulation has profound and long-term beneficial effects on the pathological FXS phenotype, thereby encouraging the use of nonpharmacological interventions for the treatment of this and perhaps other neurodevelopmental diseases.
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143
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Neuhofer D, Henstridge CM, Dudok B, Sepers M, Lassalle O, Katona I, Manzoni OJ. Functional and structural deficits at accumbens synapses in a mouse model of Fragile X. Front Cell Neurosci 2015; 9:100. [PMID: 25859182 PMCID: PMC4374460 DOI: 10.3389/fncel.2015.00100] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 03/07/2015] [Indexed: 12/26/2022] Open
Abstract
Fragile X is the most common cause of inherited intellectual disability and a leading cause of autism. The disease is caused by mutation of a single X-linked gene called fmr1 that codes for the Fragile X mental retardation protein (FMRP), a 71 kDa protein, which acts mainly as a translation inhibitor. Fragile X patients suffer from cognitive and emotional deficits that coincide with abnormalities in dendritic spines. Changes in spine morphology are often associated with altered excitatory transmission and long-term plasticity, the most prominent deficit in fmr1-/y mice. The nucleus accumbens, a central part of the mesocortico-limbic reward pathway, is now considered as a core structure in the control of social behaviors. Although the socio-affective impairments observed in Fragile X suggest dysfunctions in the accumbens, the impact of the lack of FMRP on accumbal synapses has scarcely been studied. Here we report for the first time a new spike timing-dependent plasticity paradigm that reliably triggers NMDAR-dependent long-term potentiation (LTP) of excitatory afferent inputs of medium spiny neurons (MSN) in the nucleus accumbens core region. Notably, we discovered that this LTP was completely absent in fmr1-/y mice. In the fmr1-/y accumbens intrinsic membrane properties of MSNs and basal excitatory neurotransmission remained intact in the fmr1-/y accumbens but the deficit in LTP was accompanied by an increase in evoked AMPA/NMDA ratio and a concomitant reduction of spontaneous NMDAR-mediated currents. In agreement with these physiological findings, we found significantly more filopodial spines in fmr1-/y mice by using an ultrastructural electron microscopic analysis of accumbens core medium spiny neuron spines. Surprisingly, spine elongation was specifically due to the longer longitudinal axis and larger area of spine necks, whereas spine head morphology and postsynaptic density size on spine heads remained unaffected in the fmr1-/y accumbens. These findings together reveal new structural and functional synaptic deficits in Fragile X.
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Affiliation(s)
- Daniela Neuhofer
- INSERM U901 Marseille, France ; INMED Marseille, France ; Université de Aix-Marseille, UMR S901 Marseille, France
| | - Christopher M Henstridge
- Momentum Laboratory of Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
| | - Barna Dudok
- Momentum Laboratory of Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary ; School of Ph.D. Studies, Semmelweis University Budapest, Hungary
| | - Marja Sepers
- Department of Psychiatry, University of British Columbia Vancouver, Canada
| | - Olivier Lassalle
- INSERM U901 Marseille, France ; INMED Marseille, France ; Université de Aix-Marseille, UMR S901 Marseille, France
| | - István Katona
- Momentum Laboratory of Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences Budapest, Hungary
| | - Olivier J Manzoni
- INSERM U901 Marseille, France ; INMED Marseille, France ; Université de Aix-Marseille, UMR S901 Marseille, France
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144
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Abstract
PURPOSE OF REVIEW This work reviews recent research regarding treatment of fragile X syndrome (FXS), the most common inherited cause of intellectual disability and autism spectrum disorder. The phenotype includes anxiety linked to sensory hyperarousal, hyperactivity, and attentional problems consistent with attention deficit hyperactivity disorder and social deficits leading to autism spectrum disorder in 60% of boys and 25% of girls with FXS. RECENT FINDINGS Multiple targeted treatments for FXS have rescued the phenotype of the fmr1 knockout mouse, but few have been beneficial to patients with FXS. The failure of the metabotropic glutamate receptor 5 antagonists falls on the heels of the failure of Arbaclofen's efficacy in children and adults with autism or FXS. In contrast, efficacy has been demonstrated in a controlled trial of minocycline in children with FXS. Minocycline lowers the abnormally elevated levels of matrix metalloproteinase 9 in FXS. Acamprosate and lovastatin have been beneficial in open-label trials in FXS. The first 5 years of life may be the most efficacious time for intervention when combined with behavioral and/or educational interventions. SUMMARY Minocycline, acamprosate, lovastatin, and sertraline are treatments that can be currently prescribed and have shown benefit in children with FXS. Use of combined medical and behavioral interventions will likely be most efficacious for the treatment of FXS.
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Affiliation(s)
- Randi J. Hagerman
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Health System, Sacramento, California, USA
- Department of Pediatrics, University of California Davis Health System, Sacramento, California, USA
| | - Jonathan Polussa
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute, University of California Davis Health System, Sacramento, California, USA
- Department of Pediatrics, University of California Davis Health System, Sacramento, California, USA
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145
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Tian M, Zeng Y, Hu Y, Yuan X, Liu S, Li J, Lu P, Sun Y, Gao L, Fu D, Li Y, Wang S, McClintock SM. 7, 8-Dihydroxyflavone induces synapse expression of AMPA GluA1 and ameliorates cognitive and spine abnormalities in a mouse model of fragile X syndrome. Neuropharmacology 2015; 89:43-53. [DOI: 10.1016/j.neuropharm.2014.09.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Revised: 08/28/2014] [Accepted: 09/04/2014] [Indexed: 01/20/2023]
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146
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Abstract
Fragile X Syndrome (FXS) is commonly thought to arise from dysfunction of the synapse, the site of communication between neurons. However, loss of the protein that results in FXS occurs early in embryonic development, while synapses are formed relatively late. Fragile X Syndrome (FXS) is the leading known monogenic form of autism and the most common form of inherited intellectual disability. FXS results from silencing the FMR1 gene during embryonic development, leading to loss of Fragile X Mental Retardation Protein (FMRP), an RNA-binding protein that regulates mRNA transport, stability, and translation. FXS is commonly thought of as a disease of synaptic dysfunction; however, FMRP expression is lost early in embryonic development, well before most synaptogenesis occurs. Recent studies suggest that loss of FMRP results in aberrant neurogenesis, but neurogenic defects have been variable. We investigated whether FMRP affects neurogenesis in Xenopus laevis tadpoles that express a homolog of FMR1. We used in vivo time-lapse imaging of neural progenitor cells and their neuronal progeny to evaluate the effect of acute loss or overexpression of FMRP on neurogenesis in the developing optic tectum. We complimented the time-lapse studies with SYTOX labeling to quantify apoptosis and CldU labeling to measure cell proliferation. Animals with increased or decreased levels of FMRP have significantly decreased neuronal proliferation and survival. They also have increased neuronal differentiation, but deficient dendritic arbor elaboration. The presence and severity of these defects was highly sensitive to FMRP levels. These data demonstrate that FMRP plays an important role in neurogenesis and suggest that endogenous FMRP levels are carefully regulated. These studies show promise in using Xenopus as an experimental system to study fundamental deficits in brain development with loss of FMRP and give new insight into the pathophysiology of FXS.
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147
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Araya R. Input transformation by dendritic spines of pyramidal neurons. Front Neuroanat 2014; 8:141. [PMID: 25520626 PMCID: PMC4251451 DOI: 10.3389/fnana.2014.00141] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 11/11/2014] [Indexed: 11/13/2022] Open
Abstract
In the mammalian brain, most inputs received by a neuron are formed on the dendritic tree. In the neocortex, the dendrites of pyramidal neurons are covered by thousands of tiny protrusions known as dendritic spines, which are the major recipient sites for excitatory synaptic information in the brain. Their peculiar morphology, with a small head connected to the dendritic shaft by a slender neck, has inspired decades of theoretical and more recently experimental work in an attempt to understand how excitatory synaptic inputs are processed, stored and integrated in pyramidal neurons. Advances in electrophysiological, optical and genetic tools are now enabling us to unravel the biophysical and molecular mechanisms controlling spine function in health and disease. Here I highlight relevant findings, challenges and hypotheses on spine function, with an emphasis on the electrical properties of spines and on how these affect the storage and integration of excitatory synaptic inputs in pyramidal neurons. In an attempt to make sense of the published data, I propose that the raison d'etre for dendritic spines lies in their ability to undergo activity-dependent structural and molecular changes that can modify synaptic strength, and hence alter the gain of the linearly integrated sub-threshold depolarizations in pyramidal neuron dendrites before the generation of a dendritic spike.
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Affiliation(s)
- Roberto Araya
- Department of Neurosciences, Faculty of Medicine, University of Montreal Montreal, QC, Canada
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148
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Mancuso JJ, Cheng J, Yin Z, Gilliam JC, Xia X, Li X, Wong STC. Integration of multiscale dendritic spine structure and function data into systems biology models. Front Neuroanat 2014; 8:130. [PMID: 25429262 PMCID: PMC4228840 DOI: 10.3389/fnana.2014.00130] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 10/22/2014] [Indexed: 12/27/2022] Open
Abstract
Comprising 1011 neurons with 1014 synaptic connections the human brain is the ultimate systems biology puzzle. An increasing body of evidence highlights the observation that changes in brain function, both normal and pathological, consistently correlate with dynamic changes in neuronal anatomy. Anatomical changes occur on a full range of scales from the trafficking of individual proteins, to alterations in synaptic morphology both individually and on a systems level, to reductions in long distance connectivity and brain volume. The major sites of contact for synapsing neurons are dendritic spines, which provide an excellent metric for the number and strength of signaling connections between elements of functional neuronal circuits. A comprehensive model of anatomical changes and their functional consequences would be a holy grail for the field of systems neuroscience but its realization appears far on the horizon. Various imaging technologies have advanced to allow for multi-scale visualization of brain plasticity and pathology, but computational analysis of the big data sets involved forms the bottleneck toward the creation of multiscale models of brain structure and function. While a full accounting of techniques and progress toward a comprehensive model of brain anatomy and function is beyond the scope of this or any other single paper, this review serves to highlight the opportunities for analysis of neuronal spine anatomy and function provided by new imaging technologies and the high-throughput application of older technologies while surveying the strengths and weaknesses of currently available computational analytical tools and room for future improvement.
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Affiliation(s)
- James J Mancuso
- Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute Houston, TX, USA ; TT and WF Chao Center for Bioinformatics Research and Imaging for Neurosciences, Houston Methodist Research Institute Houston, TX, USA
| | - Jie Cheng
- Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute Houston, TX, USA ; TT and WF Chao Center for Bioinformatics Research and Imaging for Neurosciences, Houston Methodist Research Institute Houston, TX, USA
| | - Zheng Yin
- Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute Houston, TX, USA ; TT and WF Chao Center for Bioinformatics Research and Imaging for Neurosciences, Houston Methodist Research Institute Houston, TX, USA
| | - Jared C Gilliam
- Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute Houston, TX, USA ; TT and WF Chao Center for Bioinformatics Research and Imaging for Neurosciences, Houston Methodist Research Institute Houston, TX, USA
| | - Xiaofeng Xia
- Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute Houston, TX, USA ; TT and WF Chao Center for Bioinformatics Research and Imaging for Neurosciences, Houston Methodist Research Institute Houston, TX, USA
| | - Xuping Li
- Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute Houston, TX, USA ; TT and WF Chao Center for Bioinformatics Research and Imaging for Neurosciences, Houston Methodist Research Institute Houston, TX, USA
| | - Stephen T C Wong
- Department of Systems Medicine and Bioengineering, Houston Methodist Research Institute Houston, TX, USA ; TT and WF Chao Center for Bioinformatics Research and Imaging for Neurosciences, Houston Methodist Research Institute Houston, TX, USA
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149
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Zhang Y, Bonnan A, Bony G, Ferezou I, Pietropaolo S, Ginger M, Sans N, Rossier J, Oostra B, LeMasson G, Frick A. Dendritic channelopathies contribute to neocortical and sensory hyperexcitability in Fmr1(-/y) mice. Nat Neurosci 2014; 17:1701-9. [PMID: 25383903 DOI: 10.1038/nn.3864] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 10/14/2014] [Indexed: 12/14/2022]
Abstract
Hypersensitivity in response to sensory stimuli and neocortical hyperexcitability are prominent features of Fragile X Syndrome (FXS) and autism spectrum disorders, but little is known about the dendritic mechanisms underlying these phenomena. We found that the primary somatosensory neocortex (S1) was hyperexcited in response to tactile sensory stimulation in Fmr1(-/y) mice. This correlated with neuronal and dendritic hyperexcitability of S1 pyramidal neurons, which affect all major aspects of neuronal computation, from the integration of synaptic input to the generation of action potential output. Using dendritic electrophysiological recordings, calcium imaging, pharmacology, biochemistry and a computer model, we found that this defect was, at least in part, attributable to the reduction and dysfunction of dendritic h- and BKCa channels. We pharmacologically rescued several core hyperexcitability phenomena by targeting BKCa channels. Our results provide strong evidence pointing to the utility of BKCa channel openers for the treatment of the sensory hypersensitivity aspects of FXS.
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Affiliation(s)
- Yu Zhang
- 1] INSERM, Neurocentre Magendie, Physiopathologie de la plasticité neuronale, U862, Bordeaux, France. [2] University of Bordeaux, Neurocentre Magendie, Physiopathologie de la plasticité neuronale, U862, Bordeaux, France
| | - Audrey Bonnan
- 1] INSERM, Neurocentre Magendie, Physiopathologie de la plasticité neuronale, U862, Bordeaux, France. [2] University of Bordeaux, Neurocentre Magendie, Physiopathologie de la plasticité neuronale, U862, Bordeaux, France
| | - Guillaume Bony
- 1] INSERM, Neurocentre Magendie, Physiopathologie de la plasticité neuronale, U862, Bordeaux, France. [2] University of Bordeaux, Neurocentre Magendie, Physiopathologie de la plasticité neuronale, U862, Bordeaux, France
| | - Isabelle Ferezou
- Laboratoire de Neurobiologie, ESPCI ParisTech CNRS UMR 7637, Paris, France
| | - Susanna Pietropaolo
- 1] University of Bordeaux, INCIA, Talence, France. [2] CNRS, INCIA, UMR 5287, Talence, France
| | - Melanie Ginger
- 1] INSERM, Neurocentre Magendie, Physiopathologie de la plasticité neuronale, U862, Bordeaux, France. [2] University of Bordeaux, Neurocentre Magendie, Physiopathologie de la plasticité neuronale, U862, Bordeaux, France
| | - Nathalie Sans
- 1] INSERM, Neurocentre Magendie, Physiopathologie de la plasticité neuronale, U862, Bordeaux, France. [2] University of Bordeaux, Neurocentre Magendie, Physiopathologie de la plasticité neuronale, U862, Bordeaux, France
| | - Jean Rossier
- Laboratoire de Neurobiologie, ESPCI ParisTech CNRS UMR 7637, Paris, France
| | - Ben Oostra
- Department of Clinical Genetics, Erasmus MC, Rotterdam, the Netherlands
| | - Gwen LeMasson
- 1] INSERM, Neurocentre Magendie, Physiopathologie de la plasticité neuronale, U862, Bordeaux, France. [2] University of Bordeaux, Neurocentre Magendie, Physiopathologie de la plasticité neuronale, U862, Bordeaux, France
| | - Andreas Frick
- 1] INSERM, Neurocentre Magendie, Physiopathologie de la plasticité neuronale, U862, Bordeaux, France. [2] University of Bordeaux, Neurocentre Magendie, Physiopathologie de la plasticité neuronale, U862, Bordeaux, France
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Stimulated emission depletion (STED) microscopy reveals nanoscale defects in the developmental trajectory of dendritic spine morphogenesis in a mouse model of fragile X syndrome. J Neurosci 2014; 34:6405-12. [PMID: 24790210 DOI: 10.1523/jneurosci.5302-13.2014] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Dendritic spines are basic units of neuronal information processing and their structure is closely reflected in their function. Defects in synaptic development are common in neurodevelopmental disorders, making detailed knowledge of age-dependent changes in spine morphology essential for understanding disease mechanisms. However, little is known about the functionally important fine-morphological structures, such as spine necks, due to the limited spatial resolution of conventional light microscopy. Using stimulated emission depletion microscopy (STED), we examined spine morphology at the nanoscale during normal development in mice, and tested the hypothesis that it is impaired in a mouse model of fragile X syndrome (FXS). In contrast to common belief, we find that, in normal development, spine heads become smaller, while their necks become wider and shorter, indicating that synapse compartmentalization decreases substantially with age. In the mouse model of FXS, this developmental trajectory is largely intact, with only subtle differences that are dependent on age and brain region. Together, our findings challenge current dogmas of both normal spine development as well as spine dysgenesis in FXS, highlighting the importance of super-resolution imaging approaches for elucidating structure-function relationships of dendritic spines.
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